Two published international patent applications namely WO2011/120057 and WO2013/044301 disclose such modules but have not, as of the priority date of the present application, been erected or constructed. The contents of both international applications are hereby incorporated into the present specification for all purposes.
A repeatedly erectable module which has four columns is disclosed in the abovementioned patent specifications. Each column is located at a corresponding corner of the module. Each column is provided with a roof hinge, a central hinge, and a floor hinge. Thus each column has three hinges. The columns fold between an initial transport configuration and an erected configuration. In the transport configuration the two main portions of the column lie alongside each other. In the erected configuration all the portions of the column are substantially aligned. Each of the hinges preferably includes two parts which overlap when the portions of the column are aligned.
In order to maintain the column portions in an aligned condition, a fastener has been intended to pass through the overlapping portions of the hinge. In a typical proposed arrangement the fastener would have a threaded shank which mates with a threaded orifice in one of the overlapping portions.
Various disadvantages are associated with this proposed method of maintaining the column portions aligned. Firstly, it takes some time to screw in each of the fasteners during the erection phase, and subsequently unscrew the fasteners if the module is to be moved. In addition, during the move the fasteners may well be lost. Thirdly, where the fasteners are provided with a conventional head such as a Phillips screw head or a slotted head, pranksters or malicious malcontents may undo the fasteners.
Furthermore, during the erection procedure it is desirable that personnel not enter the structure until the columns have been reliably placed in their erected condition and the hinges prevented from bending or otherwise giving way. Still further, during the lowering procedure, the weight carried by the columns, corrosion, and various other factors may prevent the threaded fastener being undone. Finally, it is desirable that the hinges be latched or locked into their erected position without any give since a fraction of a millimetre movement at the hinge translates into many millimetres of movement or slack at the end of the column portions.